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Atmospheric methane
About: Atmospheric methane is a research topic. Over the lifetime, 2034 publications have been published within this topic receiving 119616 citations.
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TL;DR: In this article, the authors analyzed the spatiotemporal variations in MUT-CH4 over China from 2003 to 2008, and found that an important feature in the seasonal variation in CH4 is the two peaks that exist in summer and winter in most parts of China, which was also observed in in-situ measurements at Mt. Waliguan, Qinghai Province, China (36.2879°N 100.8964°E, 3810 m).
Abstract: Spaceborne measurements by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite provide a global view of methane (CH4) distribution in the mid-upper troposphere (MUT-CH4). The focus of this study is to analyze the spatiotemporal variations in MUT-CH4 over China from 2003 to 2008. Validation of AIRS CH4 products versus Fourier transform infrared profiles demonstrates that its RMS error is mostly less than 1.5%. A typical atmospheric methane profile is found that shows how concentrations decrease as height increases because of surface emissions. We found that an important feature in the seasonal variation in CH4 is the two peaks that exist in summer and winter in most parts of China, which is also observed in in-situ measurements at Mt. Waliguan, Qinghai Province, China (36.2879°N 100.8964°E, 3810 m). Also, in the summer, only one peak existed in western and southern China since there are no more significant anthropogenic sources in winter than at any other time of the year. Further analysis of the deseasonalized time-series of AIRS CH4 in three fixed pressure layers of AIRS from 2003 to 2008 indicates that CH4 in the Northern Hemisphere has increased abruptly since 2007, with no significant increase occurring before 2007. The increase in China is generally more significant than in other areas around the world, which again correlates with in-situ measurements at Mt. Waliguan.
26 citations
TL;DR: In this article, the authors used an ensemble of six multi-tracer atmospheric inversions that have the capacity to assimilate the major tracers in the methane oxidation chain, namely methane, formaldehyde, and carbon monoxide, to simultaneously optimize both the methane sources and sinks at each model grid.
Abstract: . After stagnating in the early 2000s, the atmospheric methane growth rate has been positive since 2007 with a significant acceleration starting in 2014. While causes for previous growth rate variations are still not well determined, this recent increase can be studied with dense surface and satellite observations. Here, we use an ensemble of six multi-tracer atmospheric inversions that have the capacity to assimilate the major tracers in the methane oxidation chain – namely methane, formaldehyde, and carbon monoxide – to simultaneously optimize both the methane sources and sinks at each model grid. We show that the recent surge of the atmospheric growth rate between 2010–2013 and 2014–2017 is most likely explained by an increase of global CH4 emissions by 17.5 ± 1.5 Tg yr−1 (mean ± 1σ), while variations in CH4 sinks remained small. The inferred emission increase is consistently supported by both surface and satellite observations, with leading contributions from the tropics wetlands (~ 35 %) and anthropogenic emissions in China (~ 20 %). Such a high consecutive atmospheric growth rate has not been observed since the 1980s and corresponds to unprecedented global total CH4 emissions.
26 citations
TL;DR: The contribution of CH4 to radiative forcing at the time of stabilization is expected to be modest, provided CH4 and CO emissions do not go far beyond current rates as discussed by the authors, but in cases leading to stabilization the potential mitigation of increases in radiativeforcing by methane control could be comparable to that of CO2 control over the next century.
Abstract: Tropospheric CH4 concentration depends, according to modeled tropospheric processes, on many factors, including emissions of CH4 as well as NOx and CO. Illustrative analyses of the relation between emissions and CH4 concentration give some guidance on the role of CH4 in the stabilization of greenhouse gas concentrations. The contribution of CH4 to radiative forcing at the time of stabilization is expected to be modest, provided CH4 and CO emissions do not go far beyond current rates. However, in cases leading to stabilization the potential mitigation of increases in radiative forcing by methane control could be comparable to that of CO2 control over the next century. Whether or not this potential is realized will depend partially on the cost of deep reductions of CH4, NOx, CO, or CO2 emissions over the next century, which is not known.
26 citations
TL;DR: In this paper, the stable carbon and hydrogen isotope ratios of atmospheric methane (CH4) from western Siberia were measured to obtain information about local CH4 sources, and the isotopic source signatures could not be understood in terms of mixing of CH4 from major sources in this region, which include natural wetlands and oil/gas fields.
26 citations